U.S. patent number 4,600,077 [Application Number 06/695,168] was granted by the patent office on 1986-07-15 for microphone wind shroud.
Invention is credited to Leslie C. Drever.
United States Patent |
4,600,077 |
Drever |
July 15, 1986 |
Microphone wind shroud
Abstract
A microphone wind shroud having a integral mounting means for
being slidably mounted to an omnidirectional or unidirectional
microphone, such as those integrally mounted on video cameras. A
semi-rigid grid-like external shell shrouds the microphone head.
The shell is lined with a multilayer laminate fabric material. The
shell and laminate allow desired audio frequencies to pass and
reach the microphone head while attenuating undesired wind noises
caused by microphone movement or environmental wind conditions.
Inventors: |
Drever; Leslie C. (Panorama
City, CA) |
Family
ID: |
24791905 |
Appl.
No.: |
06/695,168 |
Filed: |
January 25, 1985 |
Current U.S.
Class: |
181/242; 181/158;
381/359 |
Current CPC
Class: |
H04R
1/086 (20130101) |
Current International
Class: |
H04R
1/08 (20060101); F01N 007/00 () |
Field of
Search: |
;181/158,242
;179/121R,179,180,184 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Fuller; Benjamin R.
Attorney, Agent or Firm: Blakely, Sokoloff, Taylor &
Zafman
Claims
Having described the above invention what is claimed is:
1. A microphone wind shroud comprising:
a resilient annular body member having cutout portions therethrough
and being opened at a first and second end;
a wind noise attenuation medium of laminate material including a
first layer of napped nylon, a second layer of open-cell
polyurethane foam, and a third layer of woven nylon securedly
maintained immediately over said cutout portions;
a hollow head member having cutout portions therethrough and having
an opening at the first end thereof, said head member being fixedly
secured to said body member about the periphery of the respective
first ends thereof forming a unitary shroud section opened at one
end for being placed over the transducing end of a microphone;
said cutout portions of said body member and said head member
comprising a flexible plastic grid of polypropylene plastic;
an annular mount section having a first end fixedly secured to said
open end of said shroud section, and a second end;
a resilient cylindrical foam insert aligned along the longitudinal
axis of said second end, and a foam retaining means between the
outer periphery of said foam insert and the inner periphery of said
annular mount section for retaining said foam insert in place such
that said microphone wind shroud is slidably securable to a
microphone by sliding said microphone through said foam insert;
whereby said wind shroud is securely maintained on said microphone
by the gripping force of said compressive foam insert;
and whereby wind noise is attenuated by said wind shroud but
desired audio frequencies pass freely therethrough.
2. The microphone wind shroud as claimed in claim 1 wherein said
annular body member comprises a substantially cylindrical
annulus.
3. The microphone wind shroud as claimed in claim 1 wherein said
annular mount member comprises a substantially cylindrical annulus
near said first end thereof, and tapers to a reduced diameter to
the terminous of said second end thereof, and wherein said annular
mount member further includes a circumferential edge along the
first end thereof which is matably and adhesively secured to the
second end of said body member.
4. The microphone wind shroud as claimed in claim 1 wherein said
foam insert comprises a foam rubber insert having an inner diameter
smaller that the outer diameter of said microphone at the area of
connection such that said foam rubber insert maintains a secure an
tight interference fit with the neck of said microphone and such
that said insert is maintained in compression thereon.
5. The microphone wind shroud as claimed in claim 1 wherein said
foam retaining means comprises open-cell plastic foam filled
between the outer circumference of said foam insert an the inner
circumference of said annular mount section such that a lightweight
shock absorbent connection is provided between said microphone and
said wind shroud.
6. The microphone wind shroud as claimed in claim 1 wherein said
head member is fixedly secured to said body member using a
polyethylene laminate to bind the periphery of the respective first
ends such that a contiguous linear profile at the joined area is
obtained.
7. A microphone wind shroud comprising:
a substantially cylindrical resilient annular body member opened at
a first end and a second end thereof;
a hemisherical hollow head member having an opening at a first end
thereof, said head member being fixedly secured to said body member
about the periphery of the respective first ends thereof thereby
forming a unitary shroud section opened at one end for being placed
over the transducing end of a microphone, said annular body member
and said annular head member being fabricated from a flexible
plastic grid of polypropylene plastic material to allow the free
passage of audio frequencies therethrough;
a wind noise attenuation meduim secured immediately over said
cutout portions including a first layer of napped nylon, a second
layer of open-celled polyurethane foam and a third layer of woven
nylon, said layers being laminated together and adhesively secured
to the inner periphery of said annular body member and said annular
head member;
an annular mount member including a substantially cylindrical
annulus near the first end thereof and a tapered section reduced in
diameter to the terminous of the second end thereof, said annular
mount member being fixedly secured to the second end of said
annular body member, and further including a circumferential
channel along the first end thereof for being matably and
adhesively secured to the circumferential edge of the second end of
said body member;
a resilient cylindrical foam rubber insert having an inner diameter
smaller than the outer diameter of a microphone at the area of
engagement between said microphone and said microphone wind shroud
such that said foam rubber insert is maintained in compression
thereon provide a secure intereference fit between the neck of said
microphone and said insert;
an open-cell plastic foam retaining means filling the gap between
the outer circumference of said foam insert and the inner
circumference of said annular mount section;
whereby said shock mount allows for the mechanical deflection of
said microphone wind shroud when mounted on said microphone without
causing damage thereto, and wherein said annular mount section
provides for absorbtion of mechanical shock to the microphone and
motor noise caused by video camera mechanisms;
an annular channel about the periphery of said annular mount
section on the first end thereof for engaging the lip of the second
end of said cylindrical body section and adhesively adhered
thereto;
whereby unwanted sound frequencies caused by the movement of air
with respect to the wind shroud are attenuated such that only
desired audio frequency sound reaches the microphone transducer.
Description
BACKGROUND OF THE INVENTION
A wide variety of applications in science, industry and
entertainment require high quality reproduction of sound using
available sound recording techniques and equipment. High-quality,
low-noise sound reproductions, for example, are of critical
importance in the television and movie industry. There, crisp,
clean voice and dialog reproduction must be achieved despite
ambient and background noise levels of moderate to high
amplitude.
One frequently encountered source of undesirable background noise
is caused by air moving relative to the sound transducing device,
which is most typically an omnidirectional or unidirectional
microphone. As a result, a "whooshing" or rushing sound is imposed
on the desired audio, thus resulting in deteriorated sound
quality.
This type of noise may occur due to environmental or operational
requirements and conditions. For example, wind noise often occurs
when a microphone is panned during an indoor shoot, whether on a
boom or simply held in hand with an extension. Likewise, such noise
may be caused by forced air movement such as by fans or dynamic
special effects equipment.
In certain applications, such as speeches or movie productions,
unidirectional microphones are used which can reject most rear and
lateral wind noise. However, this reduction is only effective at
very low relative velocities, and will not reduce head-on wind
noise. Further, unidirectional microphones are not suitable for all
applications.
There are several prior art schemes that have been employed in an
attempt to eliminate or reduce microphone wind noises. One is the
use of a foam "sock" which is pulled over the microphone head.
However, foam socks tend to physically deteriorate over time. As a
result, foam particulates often fall into the microphone head,
causing damage and reduced performance. Also, foam socks suffer the
drawback of only being effective to reduce wind noise due to very
slight breezes, up to approximately three miles per hour. This is a
severe limitation in a broad spectrum of standard outdoor and
indoor operating environments essential to the film and television
industry. To overcome this limitation, electronic filtering
techniques have been used to filter out wind noise resulting from
velocities exceeding three miles per hour. Unfortunately,
electronic filtering also attenuates desired audio frequencies,
thereby substantially degrading sound quality.
Another prior art scheme used to reduce wind noise is the use of a
gun-type microphone windshield. This device typically consists of
suspending or supporting the microphone on a pair of suspension
mounts, and enclosing the microphone in a plastic mesh cylinder
lined with a wind interfering material. The suspension mounts,
however, can obstruct the soundfield near the front of the
microphone. Also, these units include a large air space between the
interior surface of the windshield and the surface of the
microphone. Thus, the diameter of the windshield is typically 3 to
5 times larger than the diameter of the microphone, and may
intefere with a scene.
The prior art suspension mount wind shield also suffers the
drawback of being bulky and cumbersome to handle. In addition, they
are not suitable for direct mounting on home or professional video
equipment which commonly include an integral microphone, because of
their size and because they require an air gap which creates a
large diameter apparatus.
SUMMARY OF THE INVENTION
A microphone wind shroud for attenuating microphone noise resulting
from the relative movement of air with respect to a microphone is
described. The present invention is a unitary structure that is
slidably receivable onto the neck of a microphone having an
integral suspension for resiliently retaining the wind shroud in
place. The mounting means incorporates a combination closed-cell
and open-cell foam suspension support sections.
The wind shroud is a narrow cylindrical body which aligns with the
shape of the microphone and can therefore fit between the narrow
spaces provided between the microphone mount and the camera in
modern video camera equipment. A grid-like structure covered with a
multilayer laminate material provides for attenuation of undesired
wind noise of speeds of up to 25 miles per hour while allowing
desired audio frequencies, such as speech and music to pass freely
to the transducer element of the microphone. It is therefore one
object of the present invention to provide a microphone wind shroud
that can be easily and inexpensively manufactured while providing
superior attenuation over prior art attenuation methods. It is a
further object of the present invention to provide a microphone
wind shroud that is compact for being used with modern day
microphones mounted to mini-camera equipment. It is a further
object of the present invention to provide a resilient lightweight
integral wind shroud suspension mount so that mechanical deflection
and vibration is eliminated or substantially reduced without
compromising the secure fit of the wind shroud to the
microphone.
Other objects and attendant advantages of the present invention
will become more apparant upon a reading of the specification and
examination of the drawings in which, like reference numerals refer
to like parts throughout and in which:
DETAILED DESCRIPTION OF THE DRAWINGS
FIG. 1 is a plan view of the Microphone Wind Shroud.
FIG. 2 is a cross-section of the Microphone Wind Shroud taken along
Line 2--2 of FIG. 1.
FIG. 3 is a cross-section of the Microphone Wind Shroud taken along
the front section thereof.
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to an article of manufacture for
attentuating microphone noise caused by the relative motion of air
moving with respect to a microphone. Referring generally to FIG. 1,
a preferred embodiment of the present invention is shown in plan
view. The microphone wind shroud 10 consists of a substantially
cylindrical body 12, head 14, and mount 16. The cylindrical body 12
and head 14 are composed of a plastic material, such as
polyethelyene, which is formed in a gridlike pattern. The body and
head operate as a resilient protective element that protects the
microphone and gives the present invention its external form, and
simultaneously allows desired audio frequency sound waves, such as
speech or music, to pass through the grid openings.
The head 14 is a molded hemispherical section of the polyethylene
plastic grid material. The head 14 is secured to the body 12 with a
polyethylene lamination 15 or other suitable binding method so as
to form a contiguous sealed unit with the body 12. Unlike solid
plastic rings which can be crushed and do not accomodate the
resilient grid material flexibility, the plastic laminate is light
and can be deformed plastically and resiliently. Also, the laminate
is lighter than a foam and provides a low contiguous profile for
accomodating an additional one-layer of sound alternating
material.
The body may be formed from a sheet of grid material which is
formed into a cylinder and then sealed along it longitudinal seam
with a laminate or suitable adhesive. Alternatively, the body can
be formed as a unitary cylindrical structure using molding or other
forming techniques widely known in the art.
Referring now to FIG. 3 the interior surface of the body and head
are lined completely with a fabric lining 22. In the present
preferred embodiment, this lining is composed of a multilayer
laminate material.
As best illustrated in FIG. 3 the laminate includes an upper layer
of napped nylon 24, an intermediate layer of open cell polyurethane
foam 25, and a lower layer of woven nylon 26. The three layers are
glued together using a resin or other suitable adhesive. The
laminate 22 is securely affixed to the interior surface 50 of the
head and body with the napped nylon layer exposed through the grid
openings of the webbing such that the laminate conforms uniformly
to the webbing surface contour.
The laminate structure, combined with the webbing, serves as a wind
interfering and muffling medium. Thus, audio frequencies are able
to pass through the wind shroud to the microphone, while
undesirable wind noise is broken up and attenuated by the baffling
effect of the combined laminate and grid structure.
As shown in FIG. 1, the microphone wind shroud includes a mount 16
which is easily securable directly to a camera mounted microphone
or other microphone of selected dimensions. The mount 16 is a
unitary piece of molded plastic or other resilient composition
which has a body-mounting end 34 and a microphone connector end 36.
The body 12 of the wind shroud 10 is fixedly secured to the
body-mounting end 34 along channel 38. The channel has an internal
groove 39 which is matably received about the circumfrence of the
back end of the wind shroud body. The body mounting end 34 of the
mount is retained about the first lip 35 by a suitable adhesive,
such as cyanoacrylate, plastic adhesive or other suitable
adhesive.
As shown in FIG. 1, and as further illustrated in FIG. 2 showing a
cross section of the wind shroud taken along line 2--2, the mount
has a gradual taper which narrows to a reduced diameter at the
microphone connector end 36 to accomodate the neck 40 of the
microphone 42.
A closed-cell cylindrical foam insert 44 having an outer diameter
approximately equal to that of the inner diameter of the microphone
connector end 36, aligns with the microphone connector end 36 and
extends inward therefrom. It is adhesively maintained in that
position by being resiliently packed therein with open-celled
plastic foam 41 which fills the region between the inner surface 43
of the mount and the outer diameter of the insert 45. Thus, a shock
and sound absorbent connection is achieved which securedly retains
the microphone wind shroud to the microphone.
Referring generally to FIG. 2, the microphone wind shroud is shown
in its mounted condition on the integral microphone 42.
The wind shroud is mounted to this position easily by simply
sliding the wind shroud down the neck of the microphone until the
mount 16 engages with the base of the microphone neck. The mount 16
is designed to engage with the neck with a tight interference fit
such that the foam insert 44 is maintained in compression when
mounted, so that the wind shroud is retained rigidly in place.
The above-described mount 16 provides a resilient connection and
support which protects the microphone from shock and vibration and
also allows the wind shroud to be deflected if struck, without
bending or otherwise damaging the microphone. Thus, the shroud not
only substantially reduces or eliminates wind noise but also
protects the microphone head. Because of the wide variety of
environments and rugged operating conditions that video cameras are
exposed to, the physical protection to the microphone acheived by
the present invention can substantially increase the working life
of the microphone.
In addition to protecting the microphone from injury due to
droppage and the like, the present invention also provides
resistance to other mechanical and environmental intrusions such as
rain and snow. Further, unlike prior art wind noise reducing
devices like foam socks, the foam interface between the microphone,
mount and hard plastic shell that surrounds the mount of the
present invention, isolates camera motor noise eminating from video
camera auto-focus motor and other motorized internal components
thereof. Further, the sound baffling meduim of the wind shroud
dampens noise by attenuating the higher frequencies of motor noise,
which, unlike frequencies for human speech, do not pass freely
through the present invention.
The above-described mounting arrangement overcomes numerous
disadvantages of the prior art. For example, prior art wind noise
reduction schemes that are able to attenuate moderate and high wind
speeds cannot be fitted directly over the microphone. They
typically incorporate a large air gap and independent shock mounts,
requiring a diameter of 4 to 8 inches for a 1 inch diameter
microphone. They also are typically too long for many applications
because they must enclose both ends of the microphone. Such prior
art devices could not be accomodated in the small circumferential
area surrounding the microphone on modern mini-cameras used both in
the home and in industry.
Additionally, the present invention eliminates the necessity for
expensive and multiple independent shock mounts, which also require
additional manufacturing and mounting steps. There are
significantly fewer manufacturing steps required to manufacture the
present invention to provide the same anti-rumble advantages
acheived by more complicated prior art assemblies.
Physical protection not previously available in "foam sock" type
wind noise reducers, as well as increased wind noise attenuation is
also achieved by the present inventive wind shroud. Similarly,
complex electronic sound filtering, which is expensive and subject
to on-location failure and requires a power source, is unnecessary.
Thus, using the present invention, high-quality sound reproduction
can be achieved in winds up to the twenty-mile-an-hour range
inexpensively and using a minumum of space.
The fabrication of the present invention can be accomplished using
off-the-shelf plastic grid stock and laminate fabrics, and readily
available adhesive. To fabricate the wind shroud, the fabric
laminate is assembled by binding the respective laminate layers
together. The laminate composite is then heat-laminated to the
plastic grid stock. The grid is then formed into a cylinder, which
is adhesively joined at a seam along the longitudinal axis of the
cylinder by laminating a strip of polyethelyne along the aligned
seam edges. Alternatively, a pre-formed cylindrical grid can be
used and other adhesive may also be used to join the seam. The head
is molded to form a hemisphere using heat forming, or other
fabricating techniques widely known in the art. It is then mounted
to the second lip 48 of the body with polyethelyne laminate or
other suitable adhesive to the cylinder.
The mount 16 is hard-cast plastic which also can be molded extruded
or otherwise manufactured for a particular application. The
closed-cell foam rubber insert is then inserted through the end of
the mount shell to align flush therewith. The void between the
insert and inner wall of the mount is then filled with plastic
open-cell foam to provide a light and strong means to securely hold
the insert in place.
In this manner, a simple, inexpensive and effective manufacture of
the present microphone wind shroud having a substantially reduced
diameter and increased efficiency over prior art wind noise
reducing devices, is accomplished in the present invention.
* * * * *